[1] Okayama Univ, Grad Sch Med & Dent, Dept Gastroenterol Surg Surg 1, Okayama 7008558, Japan
[2] Natl Hosp Org, Iwakuni Med Ctr, Div Cardiovasc Surg, Iwakuni, Japan
[3] Natl Hosp Org, Fukuyama Med Ctr, Div Cardiovasc Surg, Fukuyama, Hiroshima, Japan
[4] Kawasaki Med Sch, Dept Surg, Div Thorac & Cardiovasc Surg, Kurashiki, Okayama, Japan